1. Field of the Invention
The present invention is directed to a reflective mirror for permitting a driver to view images from the rear of the vehicle and more particularly, it is directed to a holographic reflective mirror which can be positioned directly on the curved windshield and compensated for any slant or curve of the windshield surface relative to the line of sight of the driver.
2. Description of the Prior Art
Numerous suggestions have been made in the prior art to provide an improved rearview mirror for use on a vehicle which increases the line of sight of the observer without distorting the relative position and size of the viewed objects. Conventional rearview mirrors utilized on vehicles have generally been planar mirrors formed of a glass substrate having a reflective coating positioned on the rear surface of the glass and coated further with a protective material to prevent oxidation of the reflecting film. Such mirrors have generally been of a flat two dimensional configuration that were elongated to extend traversely across a portion of the driver's forward line of sight. Frequently, such mirrors were cantilevered from the roof of the vehicle or cantilevered directly from the interior of the windshield. The attempts to remove any blind spots from the rear view of the driver is well documented in the prior art. Suggestions have been made to utilize convex mirrors to extend the viewing angle, however, distortion generally occurs and the objects viewed through such a convex mirror appear farther away than they actually are due to the magnification of the images. Extended, elongated mirrors with a series of stepped planar reflective surfaces have also been attempted to extend the view of the driver. These mirrors, however, are bulky and provide fragmented viewing angles to the driver.
Attempts have also been made to adhere to the surface of the rear window various refractive elements to extend the line of sight or view of the driver. Again, distortion frequently occurs and an unrealistic image is frequently conveyed to the driver.
There is still a demand in the prior art to provide a reflective rearview mirror which extends the viewing angle of the driver while portraying the images in proper perspective and position to enable the driver to make the necessary decisions for the safe operation of the vehicle.